I used the Metalform 7 round magazine, with the round follower and welded baseplate. It is an excellent magazine and I used it because I'd had spotty results with 8 round magazines.
My Chief gave me a couple of 8 round Chip McCormick Power Mags. They have consistently given perfect function in maybe six 1911's, throughout a wide range of ammo including light SWC reloads. I've got a half dozen of them now don't expect to need any more 1911 magazines.